The question is, given that 4 is 'IV' and 9 is 'IX' and 900 is 'CM', does
the subtraction pattern follow for two numerals more than two 'levels'
apart, and can numerals which represent numbers starting with 5 be
subtracted? For example, would 99 be 'IC', would 450 be 'LD', and would
995 be 'VM'?

A cafe sold tea at 30 cents a cup and cakes at 50 cents each. Everyone
in a group had the same number of cups of tea and the same number of
cakes. The bill came to $13.30. How many cups of tea did each person
have?